Unusual moisture dumps rain across Inland Northwest, with more expected next weekend

Rain and flooding continued after an “anomalous” amount of moisture remained in the Inland Northwest after the weekend, the National Weather Service reported on Monday.

“The last few storm days we’ve seen, there’s been an abnormal amount of moisture that these storms are able to tap into, and that’s what creates the storms and showers we’ve been seeing in this area,” weather service meteorologist Steven Van Horn said. “The atmosphere was quite unstable. It didn’t take much for the storms to develop.”

About 10-20 small storm systems tracked through Eastern Washington into North Idaho between 10 a.m. Sunday morning and 10 a.m. Monday morning, Van Horn said. The storm systems followed the same pattern from the weekend, producing anywhere between a half-inch to an inch of rain in about an hour, he added.

Most of the storms were in the Lewiston-Clarkston and Pullman areas, although there was also reported flooding in the Wenatchee area, Northeastern Washington and south of Priest Lake, which also saw half-dollar sized hail on Sunday evening.

Power outages were reported in Chelan due to wind damage, Van Horn said. About 6,700 customers were affected by the outage at 1:19 p.m., but power was restored in less than an hour, noted Chelan PUD spokeswoman Rachel Hansen.

Avista also reported outages in the Sandpoint and St. Maries areas, as well as minor outages in Spokane, on Monday.

The latest weather brought the total precipitation in the Spokane area to 8.16 inches, which is closer to the regional average this time of year, according to the National Weather Service’s average this time of year. Total precipitation in the Spokane area had been lower than average by almost an inch until June 1.

The weather service reported 10 flash flood warnings, eight severe thunderstorm warnings and two flood advisories on Sunday.

The wet weather will decrease when temperatures begin to rise throughout the week, Van Horn said.

More moisture is likely to develop throughout the Inland Northwest this weekend. This level of moisture is not common for this time of year, Van Horn said.

“Right now, the concern is the increased moisture over the Cascades,” he said. “The rain and snowmelt in the Cascades is something we’re concerned with for flooding impacts – that could include rock slides and mud slides.”